Heating device and automatic control means therefor



April 1951 c. M. WHEELOCK 2,549,952

HEATING DEVICE AND AUTOMATIC CONTROL MEANS THEREFOR Filed July 10, 19473 Sheets-Sheet 1 L 60 Q 70 f0 7L5 6'1 2 o.. 65" H53 JZL/w 73 f H57 40' f*f 7 72 0 H I? o 15 2 71 April 24, 1951 c, WHEELQCK 2,549,952

HEATING DEVICE AND AUTOMATIC CONTROL MEANS THEREFOR Filed July 10, 19473 Sheets-Sheet 2 V 7v o A a? 25 C5? C7 -Eik" April 24, 1951 c. M.WHEELOCK 2,549,952

HEATING DEVICE AND AUTOMATIC CONTROL MEANS THEREFOR Filed July 10, 1947Y 3 Sheets-Sheet 3 Patented Apr. 24, 1951 UNITED STATES PATENT OFFICEHEATING DEVICE AND AUTOMATIC CONTROL MEANS THEREFOR Carlton M Whcelock,Milwaukee, Wis.

Application July 10, 1947, Serial No. 760,060

2 C a ms 1 This invention relates to heating plants and has moreparticular reference to heating plants of the type having a combustionchamber in which fluid fuel is burned to provide a source of heat.

In a more specific sense this invention concerns gas fired furnaces, andit is the primary object of this invention to provide an improved burnerunit for such furnaces along with a novel electrical control system forautomatically controlling the supply of. fuel to the burner unit in amanner which assures a substantially continuous supply of heat to anenclosure such as a room heated by the furnace whenever heating of theroom is required.

In order to assure a substantially constant supply of heat-to the roomwhenever heating is required, it has previously been suggested to pro.-vide the combustion chamber of the furnace with a burner controlled bytemperature responsive devices which act to regulate the quantity offuel fed to the burner so as to vary the height of the flame produced bythe burner unit in accordance with the demand for heat. While heating inthis manner presented an advantage over the conventional types of gasfired furnaces wherein the supply of fuel to the burners is controlledin such a manner that. the burner is either on or off, it wasnevertheless objectionable since it. was in evitable that the regulationof the supply of fuel to the burner unit-made it impossible to operatethe burner unit at a uniform high level of chiciency.

With these objections to past furnace systems in mind, it is anotherobject of the present invention to provide a heating plant with 2.p111.- rality of individual burner elements each of which is controlledseparately by an electrical control system which is in part responsiveto the temperature obtaining outdoors and in part to the temperatureobtaining in the room or other enclosure heated by the furnace, with thecon.- trol system operating to maintain at least one burner elementoperative during cold weather conditions.

A further object of this invention resides in the provision of anexceptionally compact burner unit comprising a number of individualburner elements nested one within the other.

. With the above andothergobjects in view, which will appear as thedescription proceeds, this invention resides in the novel construction,com.- bination and arrangement of parts substantially as hereinafterdescribed and more particularly defined by the appended claims. it beingunderstood that such changes in the precise embodiment .of thehereindisclosed invention may .be made as come within the scope of theclaims.

The accompanying drawings illustrate several complete examples of thephysical embodiment of the invention constructed according to the bestmodes so far devised for the practical ap: plication of the principlesthereof, and in which:

Figure. l is a combined plan view of the burner unit of this invention,and electrical diagram illustrating the automatic control means for gov:erning the supply .of fuel to said burners;

Figure 2 is a bottom view of the burner unit shown in Figure 1';

Figure 3 is a, sectional view through. the burner unit taken on theplane of the line 3-73 of Fig.- ure 1;

Figure 4 is a sectional view through the burner unit taken on the planeof the line 4T4 in Fig..- .ure 1;

Figure 5 is a front. elevation of the burner unit; and

Figure 6 is a diagrammatic view illustratinga slightly modifiedelectrical control system for the burner unit of this invention.

efer in now mor particula y to th companying drawings in which likenumerals indie ate l k parts. th n mer l L0 ener lly. desisnates theburner'unit of this invention. The unit c mp s a p li y of bow -spedhumerelements, in the present instance three, the smallest burnerelement H nesting within a larger elege =1 an h ne t n ements I l and i2bein nest i th lar e t l m nt 3- E h of t o -sh red burner e em nts hasa hollow wall l4 and a hollow rirn l5 extending continuously around theupper edge of the wall with its interior communicating with the interiorof the wall. All of the rims have ports loin upper surfaces thereofthrough which gas delivered or distributed into the interior of the rimsfrom their hollow Walls is adapted to issue to burn in a flame. I

Cooperating feet 18 on the underside of; the rim of the innermost burnerelement and the. upper side of the wall for the intermediate burner unit12 are provided to support the smallest burner element on theintermediate burner elemerit; while ledges .2 0 projecting inwardly fromthe wall of the largest burner element -just lee.- neath the rim thereofprovide supports which the rim of the intermediate burner element I2 resIt i impo t t t note th the cooper.- ating feet I8 and the ledge 20position the rims the largest burner element 13 for distribution I intothe interior of the hollow rim thereon by means of a manifold tube 25.The inner end portion of the tube connects with a' bottom portion of thewall of the burner element J3 as at 26, substantially at the common axisof the concentric rims, and the tube extends forwardly I I I from theburner unit at right angles to said axis I to pass beneath the rims l 5a substantial distanceof the tube is adapted to connect with a source ofgas under pressure, the injection of gas into the tube drawing in airfor admixture with the gas in the usual manner. The resultingcombustible mixture is delivered into the interior of the hollow wall [4and thence into the interior of the hollow rim on the largest burnerwhere it may issue through the ports I6 to burn in a flame.

' The intermediate burner element [2 is likewise provided with amanifold tub 35, the inner end portion of which connects with a bottomportion of the wall of the element 12 with the tube extending forwardlytherefrom above and to one side of the tube25 but in substantiallyparallel relationship therewith. The tube projects through the aperture21 in the wall M of the largest burner elementand extends forwardly inthe same direction as the tube 25 so as to likewise pass beneath therims but at a spacing therebeneath less than that of the tube 25.

The manifold tube'32 for the smallest burner element has its inner endportion connected with the bottom portion of the wall of the element Hwith the tube lying at the side of the centrallydisposed manifold tube25 remote from the tube 30' for the intermediate burner element. Thetube 32 likewise projects through an aperture 34 in the wall of theintermediate burner element l2 in line with th aperture 21 of thelargest burner element, and through the latter aperture so as to liedirectly beneath the rims at an elevation above the remaining twomanifold tubes but in substantially parallel relationship therewith.

The outer ends 28 of the tubes 30 and 32 are in all respects similar tothat of the tube 25 hereinbefore referred to.

y The nested together burner elements describe provide a compact burnerunit wherein all of the manifold tubes have their forward endsconvenientl grouped and accessible for connection with individual gassupply ducts diagrammati-e cally illustrated in Figure 1 and numbered25' for the largest burner element, 30' for the interme diate burnerelement and 32 for the smallest burner element. a

In accordance with this invention the supply of fuel to the differentburner elements of the burner unit is adapted to be individuallycontrolled automatically partly in accordance with outdoor temperatureand partly in accordance with the temperature obtaining within the roomor enclosure heated by the burner unit. Electrical instrumentalities nowabout to be described are provided for this purpose.

These 'instrumentaliti'es include electromagnetic valves 35, 36, and 31connected in the ducts 32, 36 and 25 for the small burner element, theintermediate burner element and the largest burner element respectively,and the valves are positioned between the inlets to the manifold tubesand a main gas duct 38 with which all of the u F lets e The maingassupply duct 38 is adapted to deliver gas under pressure to theindividual suppl duct for each of the burner elements through manuallyoperable valves 30 in the individual supply ducts which enable thesupply of gas to any or all of the burner elements to be closed off atwill. In practice, it is to be understood that by-pass connections wouldbe provided leading around each of the electromagnetic valves to enablemanual operation. of the burner unit in case of electric power failure.

Separate energizing circuits s5, 66, and 4! are provided for theelectromagnetic valves 35, 36 and 37 respectively. These energizingcircuits include a common source ofE. M. F., in the present case thesecondary '48 of a step-down transformer 69, and two groups and 5| ofthermostatically operated switches. The group of switches 50 comprisesthree thermostatically operated switches 53, 54 and 55, one for each ofthe individual burner elements, and all adapted to be subjected to thetemperature obtaining outdoors. The group 5| likewise comprises. threethermo-i statically operated switches 56, 5'! and 58, one for each ofthe individual burner elements, and all adapted to be subjected to thetemperature obtaining in the room or enclosure heated bythe burner unit.

The energizing circuit 45 for the valve 35 controlling the supply offuel to the smallest burner elements ll leads from one side of thesecondary 45 of the transformer and continues serially through theswitch 53, the coil of the valve 35 and the switch 56 in'the ordernamed, and is completed at the opposite side of the secondary 48. Hencewhen both the outdoor thermostatic switch 53 and the indoor thermostaticswitch 56 are closed, the valve 35 is caused to open to enable fuel toflow into the smallest burner element ll.

In like manner, the switches 54 and 51, when closed, cause opening ofthe electromagnetic valve 36 to effect delivery of fuel to theintermediate burner 12; with closure of the switches "'55 and 58 causingthe valve 31 to be opened to effect the delivery ofgas to the largestburner 13.

It will beobvious, therefore, that when either of the pair ofthermostatic switches of each circuit is open the electromagnetic valvein said circuit will remain closed precluding the delivery of fuelto itsburner element. Y

It is also to be understood that the burner elements are provided withone or more pilot burners, andthat conventional electrical equipment isemployed to close the main supply duct 38 in the event of pilot failure.I I

In order that the roomor'other enclosure be ing heated by the burner"unit may receive a substantially constant supply of heat whenever theoutdoor temperature drops below a predetermined value at which heatingof the enclosure is necessary, this invention contemplates setting allof the thermostatic switches of the two groups 50 and 51 to close atdifferent temperatures. The following is given as an example of themanner in which the thermostatic switches may be set.

The outdoor thermostatic switch 53 for the smallest burner element llmay be set to close upon a drop in outdoor temperature to 65 F.; theoutdoor thermostatic switch 54 for the intermediate burner l2 may be setto close when the outdoor temperature drops to 40 F.; and the outdoorthermostatic switch 55 for the largest burner 13 may be set to closewhen the outdoor temmaintain the room or other enclosure heated by theburner unit at a comfortable value as long as the outdoor temperaturedoes not drop below the 40 setting for the thermostatic switch 54; thatthe intermediate burner element l2 should have a heating capacity suchthat it and the smallest burner element II are capable of furnishing allof the heat required to maintain the temperature of the room or otherenclosure at a comfortable value as long as the outdoor temperature doesnot drop below the 15 setting for the thermostatic switch 55; and thatthe largest burner element l3 should have a heating capacity such thatit andthe other two burner elements are capable of f :nishing all of theheat necessary to maintain the room or enclosure at a comfortable valuefor any outdoor temperature below 15 F; or in other words, in relativelycold weather. I

The indoor thermostatic switch 56 may be set to close upon a drop inroom temperature to 73; the switch 57 set to close at 72, and the switch58 set to close at 71. These temperatures at which the indoorthermostatic switches close, though slightly different, may yet beconsidered to be comfortable room temperatures, and it will be notedthat there is only a 2 difierential between the settings for theswitches controlling the largest and smallest burners. If there isnoticeable lag in the critical responding temperatures for the switches56, 57 and 58, these switches may be set to close over an expanded rangepresenting a greater differential in degrees between the settings of theswitches for the largest and smallest burner elements, as for instance,74, 72, and 70 for the switches 56, 51 and 58 respectively.

Operation Assume that on a relatively cool day the outdoor temperaturedrops to 60 R, which is a value sufiiciently low to effect closure ofthe outdoor thermostatic switch 53. Energization of the electromagneticvalve 35 may not necessarily occur immediately upon closure of theswitch 53 unless the indoor temperature is below 73. However, it isconceivable that the room temperature may be slightly ab0Ve73 but thatloss of heat shortly lowers the room temperature to 73 or a bit lower.Such drop in room temperature causes the indoor thermostatic switch 56to close,

and with both switches 53 and 56 closed the energizing circuit 45 iscompleted to the solenoid of the valve 35 to cause the same to open.Opening of the valve 35 efiects the delivery of gas (and air) to thesmall burner element II from whence thecombustible mixture distributedto the hollow rim l5 thereof issues to be ignited by the pilot flame,not shown, and the element II is now in operation.

If there is no further drop in outdoor temperature the smallest burnerelement l I has sufficient heating capacity to supply all the heatnecessary to return the room temperature to the value at which thethermostatic switch 56 opens, namely 73 or slightly thereabove if theinstrument lags. Immediately upon opening of the switch 56, the smallburner element II i rendered inoperative by closure of the valve 35.

In the event the temperature outdoors drops to below 40 but remainsabove 15 F., both outdoor switches 53 and 54 will be caused to close,and when the room temperature drops to 72 or slightly below, the indoorswitch '51 also closes. Both energizing circuits and 46 for the valves35 and 36 are now completed by the pairs of thermostatic switchestherein, and both the smallest burner fl and the intermediate burnerelement [2 are rendered operative by opening of the valves 35 and 36 sothat the heating capacity of the two burner elements is additive.

The temperature of the room or enclosure is thus shortly restored to the72 value or a slight amount thereover so as to cause the switch 51 toopen and render the intermediate burner element l2 inoperative byclosure of its valve 36. The smallest burner element II will remainoperative, however, since its indoor thermostatic switch 56 will remainclosed by reason of the room temperature being less than 73.

If the outdoor temperature remains at a value above 15 but less than 40,the smallest burner will remain on continuously since it cannotsupply'suflicient heat for the room at such outdoor temperatures. Theintermediate burner l2, however, will be turned on and offintermittently by the control system as the room temperature fluctuatesto values slightly above and slightly below the 72 setting for thethermostatic switch 5?.

In like manner, if the temperature drops to below the 15 setting for theoutdoor switch 55, the smallest and the intermediate size burner elementwill not have a sufficient heating capacity to supply all of the heatnecessary to maintain the room at a comfortable room temperature, andwill remain on continuously. In this case the room thermostatic switch58 will close to render the largest burner element ef: fective as theroom temperature drops to 71 or slightly less, and will be periodicallyopened and closed as the temperature in the room or enclosure fluctuatesbetween values slightly above and slightly below the 71 setting for theswitch 58 by the intermittent operation of the largest burner element [3controlled by the switch 58.

If desired, a master thermostatic switch 60 may be connected ahead ofthe group 55 of outdoor switches between them and the secondary of thetransformer and is preferably set to open upon a rise in outdoortemperature to a value approaching comfortable room temperature, as forinstance 68 to 70. With the switch 60, the supply of gas to all of theburners is shut 01f whenever the outdoor temperature rises sufncientlyto effect opening of the switch 60, as this switch when opened, causessimultaneous deenergization and closure of all of the valves 35,

36 and 31.

In the control system diagrammatically illustrated in Figure 6, separateoutdoor thermostatic) Switches similar to those previously described areprovided for each of the burner elements, but only one indoorthermostatic switch 65 is provided for all of the elements. With thissystem it is assumed that the indoor thermostat 65 will be set tomaintain a comfortable room temperature as for instance 72. Whenever itcloses upon a drop in room temperature below the desired value, thoseburner elements whose outdoor thermostatic switches are closed will beset into operation to return the indoor temperature to the desiredvalue. In this instance, however, none of the burner elements will beoperated continuously but heat roughly proportional to the degree ofcold obtaining outdoors will be supplied to the room or enclosure.

In both systems, the individual control of the burner elements in themanner described enables the different burner elements to be adjusted tooperate at maximum efficiency. This is possible because of the fact thatthe burner elements are either fully on or fully off, and are neveroperated partially on.

From the foregoing description taken together with the accompanyingdrawings, it will be apparent that this invention provides anexceptionally compact burner unit comprised of nesting burner elementsand that the control system for automatically governing the operation ofthe individual burner elements functions to assure a nearly constantsupply of heat to a room or enclosure whenever heating is required.

What I claim as my invention is: V

1. In combination with a plurality of fluid fuel burners each having aseparate supply duct, an electrical control system for governing thesupply of fuel to said burners comprising: an electromagnetic valve inthe supply duct for each of said burners; an energizing circuit for eachof said electromagnetic valves, each of said circuits including athermostatically operated switch adapted to be subjected to thetemperature obtaining outdoors and a second thermostatically operatedswitch adapted to be subjected to the temperature obtaining indoors inthe space heated by the burners, closure of both of saidthermostatically operated switches being required to effect energizationof the electromagnetic valve controlled thereby, the thermostaticallyoperated switches subjected to indoor temperature being set to closesuccessively upon a drop in indoor temperature of a relatively few'degrees, and the thermostatically operated tures which aresubstantially higher than their associated outdoor thermostaticallyoperated switches.

2. In combination: a pair of fluid fuel burners having independent fluidfuel supply ducts leading thereto; an electromagnetic valve in each ofsaid supply ducts for controlling the supply of fuel to the burners; anenergizing circuit for the electromagnetic valve controlling the supplyof fuel to one of said burners including a pair of thermostaticallyoperated switches one of which is subjected to the temperature obtainingoutdoors and the other of which is subjected to the temperatureobtaining indoors in the space heated by the burners, the indoor switchbeing set to close at a predetermined room temperaswitches being set toclose at different temperature which it is desired to maintain and theoutdoor switch being set to close at a predetermined temperature whichis substantially less than the critical responding temperature of theindoor switch, closure of both of said switches being required to effectenergization of the electromagnetic valve associated therewith; and anenergizing circuit for the electromagnetic valve controlling the supplyof fuel to the other of said burners, said last named circuit likewiseincluding a pair of thermostatically operated switches one of which issubjected to outdoor temperature and the other of which is subjected tothe temperature obtaining within the space heated by the burners, saidlast named outdoor switch being set to close at a temperaturesubstantially less than the first named outdoor switch, and said lastnamed indoor switch being set to close at a room temperature relativelyclose to but less than the critical responding temperature of the firstnamed indoor switch, closure of both switches in said last namedenergizing circuit being required to effect energization of theelectromagnetic valve controlling the flow of fuel to said other burner.

CARLTON M. WHE'ELOCK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,134,114 Evans Apr. 6, 19151,932,269 Harrington Oct. 24, 1933 2,139,344 Anderson Dec. 6, 19382,168,680 Norgren Aug. 8, 1939 2,180,789 Browning Nov. 21, 19392,289,082 Stevenson July '7, 1942 2,300,560 Faber Nov. 3, 1942 2,329,682Alfery Sept. 14, 1943 2,383,641 Focke Aug. 28, 1945

